Filter conveyor band for a continuously operating filter press

ABSTRACT

There is disclosed a filter conveyor band or belt for a continuously operating filter press, preferably of the vertical type, which includes hingedly interconnected links having drainage grooves extending longitudinally of the link with the forward ends of the grooves being open and means being provided to close the rearward ends of the grooves. There are longitudinally extending ribs that separate the grooves with such ribs having forward ends that are inclined forwardly of and away from the top surface of the ribs. The means that close the rear ends of the grooves including a rear surface as regards the direction of movement that is inclined correspondingly to the inclination of the forward ends of the ribs so that such forward ends of the ribs of a trailing link cooperate with such rear surface of a preceding link to be in at least approximately adjoining relation with such rear surface when the band is straight and to define a gap which narrows in the direction away from the tops of the ribs when the band is curved.

United States Patent Assignee said l-lans Gujer, by said Karl Koller Priority July 2, 1968 Switzerland FILTER CONVEYOR BAND FOR A CONTINUOUSLY OPERATING FILTER PRESS 5 Claims, 4 Drawing Figs.

US. Cl 210/324, 100/118, 210/401 Int. Cl .i B01d 33/04, B30!) 9/02 Field of Search 100/ l 18,

[56] References Cited UNITED STATES PATENTS 3,453,951 7/1969 Malarkey. Jr 2l0/401X Primary Examiner-Frank A. Spear, Jr. Attorney-Werner W. Kleeman ABSTRACT: There is disclosed a filter conveyor band or belt for a continuously operating filter press, preferably of the vertical type, which includes hingedly interconnected links having drainage grooves extending longitudinally of the link with the forward ends of the grooves being open and means being provided to close the rearward ends of the grooves. There are longitudinally extending ribs that separate the grooves with such ribs having forward ends that are inclined forwardly of and away from the top surface of the ribs. The means that close the rear ends of the grooves including a rear surface as regards the direction of movement that is inclined correspondingly to the inclination of the forward ends of the ribs so that such forward ends of the ribs of a trailing link cooperate with such rear surface of a preceding link to be in at least approximately adjoining relation with such rear surface when the band is straight and to define a gap which narrows in the direction away from the tops of the ribs when the band is curved.

IPATENTEI] JUN 1 m:

illlIlTlllllllJl JJ I N VENTORS BACKGROUND OF THE INVENTION The invention relates to a filter conveyor band for a continuously operating filter press having links hingedly joined with one another and including flowoff, discharge or drainage means.

The prior art reveals quite a number of continuously operating filter presses, particularly of the vertically arranged type. Although these filter presses possess quite a number of decisive advantages, they are not satisfactory because their practical construction as well as their mode of operation possess serious drawbacks. More particularly, the withdrawal of the filtered out liquid on the rear side of the filter band or filter conveyor band, respectively, presents decisive difficulties. Heretofore it has not been possible to remove the pressed out liquid in sufficient quantity from the rear side of the filter band or filter conveyor band, respectively, at the end of the filter press operation, so that the pressed matter, after leaving the press zone partly sucks up liquid again.

SUMMARY OF THE INVENTION The object of this invention is to obviate the aforementioned drawbacks and to create a filter conveyor band which will ensure perfect withdrawal of the liquid from the filter surface.

Therefore, the filter conveyor band of this invention is characterized such that each link of the band is equipped with drainage grooves representing the flowoff means which are separated by longitudinal ribs and which when viewed in the conveying direction, are closed off at their rear and which in the forward area are opened forwardly and toward the rear side of the link, with the forward ends of the longitudinal separating ribs being included forwardly and away from the filter surface, so that these ribs cooperate with a cleat or strip at the rear of the preceding link member, said cleat or strip extending transversely in relation to the direction of movement of the band, said cleat or strip being correspondingly inclined, and where said cooperation takes place in such manner that the forward ends of the ribs, with the filter conveyor band being stretched, at least approximately adjoin said cleat or strip, so as to form slots when the filter conveyor band curves with such slots narrowing away from the filter surface.

The drainage grooves extending in conveying direction enable perfect withdrawal of the liquid from the filter surface. This liquid, when viewed in conveying direction, can flow off at the forward end of one link toward the rear side of the preceding link. Where the filter conveyor bands in a filter press are arranged vertically, the withdrawal of the liquid from the lower end of a link is aided by the cleat or strip of each respective preceding link, said cleat or strip having an inclination which slants forwardly and away from the filter surface, in that the liquid is additionally deflected onto the rear side of the respective preceding link. The slanted inclination of the forward ends of the ribs separate the drainage grooves as well as of the rearward cleat or strip of the preceding link making it also possible to perfectly withdraw the liquid from the filter surface after completion of the pressing operation and at the lower end of the press cavity since the capillary action between the forward ends of the ribs and the rearward strip of the preceding link retain the pressed out liquid and drain it off the filter surface. This action is above all, also present when the filter conveyor band is deflected into a curve from its stretched condition. In this case, the forward ends of the ribs and the rearward cleat or strip of the immediately preceding link form slots which narrow in the direction away from the filter surface, Here also, the narrowing preferably extends to such an extent that the ends of the slots possess a capillary action. As a result, the liquid is drained off safely from the filter surfaces.

BRIEF DESCRIPTION OF THE DRAWINGS Further and more specific objects and advantages of the invention will become readily apparent from the following detailed description taken in connection with accompanying drawings in which:

FIG. 1 is a fragmentary top plan view illustrating a link of the filter band or belt in accordance with the teaching of this invention;

' FIG. 2 is a longitudinal cross-sectional view taken along line 11-11 of FIG. 1;

FIG. 3 is a fragmentary longitudinal cross-sectional view illustrating two adjacent and connected links as they appear when the filter band or belt is in straight condition; and

FIG. 4 is a similar view illustrating the links as they appear when the filter band or belt is curved.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1 and 2 illustrate a link of the filter conveyor band or belt which is equipped with drainage grooves 1. The individual drainage grooves are separated from one another by ribs 2. The ends 3 of the drainage grooves that are the rear ends as regards the direction of movement, are closed off by a strip or web 5 which is inclined forwardly and away from filter surface 4. The forward ends 6 of the drainage grooves are open forwardly and towards the rear side of the link. The forward ends 7 of ribs 2 are likewise inclined forwardly and away from conveying surface 4, withthis inclination corresponding to that of strip 5. An opening 8 is provided at the rear end of the link, with this opening penetrating ribs 2 and reaching into drainage grooves 1. The opening 8 which is disposed transversely in relation to the conveying direction, provides for aerating the drainage grooves so that no subatmospheric pressure can form in the latter.

At the forward and rearward ends, the link is equipped with eyelets 9 and 10 which are offset relatively to one another and serve to connect the individual links with one another. At the same time, these eyelets serve as teeth which cooperate with a drive or guide chain wheel or sprocket means, respectively, of a filter press. 0n the rear side of the link, there are provided longitudinally extending support strips 11, that serve on the one hand for reinforcing the link and on the other hand for holding a supporting device in a filter press.

The links of the filter conveyor band consist preferably of plastic. Polyoxymethylene known commercially as Delrin has proven to be particularly useful.

The mode of operation of a filter conveyor band or belt disposed in a vertical filter press or tower is as follows:

Two filter conveyor bands together form a downwardly narrowing filter press cavity and are covered with a filter cloth at filter surface. The filter conveyor band travels downwardly, thereby pressing out the pressed matter. The extracted liquid enters into drainage grooves l and fiows off downwardly until it meets the rear surface of web or strip 5 of the preceding link. By virtue of the slanted inclination of this web or strip, the liquid is deflected onto the rearward side of the link and can emerge rearwardly through the opening of the grooves. Since the ends 7 of ribs 2 have an inclination which corresponds to that of web or strip 5, adjoining the latter at least approximately, a slot is formed between the forward ends 7 of ribs 2 and the rear surface of strip 5 whose capillary action aids a frictionless withdrawal of the liquid. The flow path of the emerging liquid in the links of the filter conveyor band is depicted in FIG. 3 by a dashed line. In order to prevent formation of a subatmospheric pressure condition in the drainage grooves 2 as a result of the emerging liquid which would impede the drainage of the liquid, the openings 8 in ribs 2 in their rearward area, that extend transversely in relation to the conveying direction, admit air.

At the lower end of the press cavity, the filter conveyor bands are deflected and thereby release the filter cake. In order to prevent that, possible residual drops are again taken up by the slackened filter cake during the deflection of the filter conveyor bands, the links are constructed such that they form a slot during deflection, such slot being formed between forward ends 7 of the ribs of each rearward or trailing link and the rear surface of strip of the preceding link. This slot narrows in the direction extending away from the plane of filter surface 4. As a result, the capillary force is produced in the slot at the side facing away from the filter surface, said capillary force drawing off rearwardly even the last drop of liquid from the filter surface. Thus, a perfect and heretofore unknown drainage of the liquid from the filter surface or from the filter cloth, respectively, is achieved.

Therefore, it should be apparent from the foregoing description that the objects and advantages set forth at the outset to the specification have been successfully achieved, ACCORDINGLY,

We claim:

1. A filter conveyor band for a continuously operating press including a plurality of hingedly interconnected links, each link comprising a body having drainage grooves extending in the direction of movement of the band, means closing the rear end of each groove, each groove being open at its forward end, ribs extending longitudinally of the body and separating said grooves, said ribs including a forward end, that is inclined forwardly of and away from the plane of the tops of said ribs, and the means closing the rear end of each groove having a rear surface as regards the direction of movement of said band that is inclined correspondingly to the inclination of the forward end of the said ribs whereby said forward ends of said ribs cooperate with said rear surface so as to at least approximately adjoin such rear surface when the band is in straight condition and to define a gap which narrows in a direction away from the tops of said ribs when the band is in curved condition.

2. A filter conveyor band as claimed in claim 1 and the rear ends of each rib having aeration openings therein that extend transversely in relation to the conveying direction.

3. A filter conveyor band as claimed in claim 1 and teeth means on the rear side of each link for cooperation with a driving means.

4. A filter conveyor band as claimed in claim 1 and said links consisting of plastic material.

5. A filter conveyor band as claimed in claim 4 and said plastic material consisting of polyoxymethylene. 

1. A filter conveyor band for a continuously operating press including a plurality of hingedly interconnected links, each link comprising a body having drainage grooves extending in the direction of movement of the band, means closing the rear end of each groove, each groove being open at its forward end, ribs extending longitudinally of the body and separating said grooves, said ribs including a forward end, that is inclined forwardly of and away from the plane of the tops of said ribs, and the means closing the rear end of each groove having a rear surface as regards the direction of movement of said band that is inclined correspondingly to the inclination of the forward end of the said ribs whereby said forward ends of said ribs cooperate with said rear surface so as to at least approximately adjoin such rear surface when the band is in straight condition and to define a gap which narrows in a direction away from the tops of said ribs when the band is in curved condition.
 2. A filter conveyor band as claimed in claim 1 and the rear ends of each rib having aeration openings therein that extend transversely in relation to the conveying direction.
 3. A filter conveyor band as claimed in claim 1 and teeth means on the rear side of each link for cooperation with a driving means.
 4. A filter conveyor band as claimed in claim 1 and said links consisting of plastic material.
 5. A filter conveyor band as claimed in claim 4 and said plastic material consisting of polyoxymethylene. 